Highly nonrandom features of synaptic connectivity in local cortical circuits

How different is local cortical circuitry from a random network? To answer this question, we probed synaptic connections with several hundred simultaneous quadruple whole-cell recordings from layer 5 pyramidal neurons in the rat visual cortex. Analysis of this dataset revealed several nonrandom feat...

Full description

Saved in:
Bibliographic Details
Published in:PLoS biology 2005-03, Vol.3 (3), p.e68-e68
Main Authors: Song, Sen, Sjöström, Per Jesper, Reigl, Markus, Nelson, Sacha, Chklovskii, Dmitri B
Format: Article
Language:English
Subjects:
Animals
Binomial distribution
Cell Communication - physiology
Confidence intervals
In Vitro Techniques
Neural Pathways - physiology
Neuronal Plasticity
Neurons
Neurons - physiology
Neuroscience
Rats
Rattus (Rat)
Signal Transduction
Standard deviation
Statistical methods
Studies
Synapses - physiology
Visual Cortex - physiology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:How different is local cortical circuitry from a random network? To answer this question, we probed synaptic connections with several hundred simultaneous quadruple whole-cell recordings from layer 5 pyramidal neurons in the rat visual cortex. Analysis of this dataset revealed several nonrandom features in synaptic connectivity. We confirmed previous reports that bidirectional connections are more common than expected in a random network. We found that several highly clustered three-neuron connectivity patterns are overrepresented, suggesting that connections tend to cluster together. We also analyzed synaptic connection strength as defined by the peak excitatory postsynaptic potential amplitude. We found that the distribution of synaptic connection strength differs significantly from the Poisson distribution and can be fitted by a lognormal distribution. Such a distribution has a heavier tail and implies that synaptic weight is concentrated among few synaptic connections. In addition, the strengths of synaptic connections sharing pre- or postsynaptic neurons are correlated, implying that strong connections are even more clustered than the weak ones. Therefore, the local cortical network structure can be viewed as a skeleton of stronger connections in a sea of weaker ones. Such a skeleton is likely to play an important role in network dynamics and should be investigated further.
ISSN:1545-7885
1544-9173
1545-7885
DOI:10.1371/journal.pbio.0030068